What is a step sequencer?
Step sequencers were originally hardware modules. They produced a limited number of control signals in a steady, pulsed sequence that kept repeating until deactivated. The output of the signal could be sent to some other synthesizer module, such as an oscillator or audio filter. If you sustained a single note while the step sequencer was active, the changing voltage, when assigned to the frequency of an oscillator, would produce a repeating sequence of changing pitches.
Step sequencers continue to evolve. Practical application grew to include such things as triggering synthesized drum sounds (often called “pattern sequencers”), modulating the amplitudes of sounds and controlling the cutoff and center frequency of audio filters. Today, you can assign the output of a step sequencer to almost any function on a synthesizer. You can use them to control oscillator frequency (pitch), amplitude, and a filter cutoff.
The typical step sequencer has a set of controls that allow the user to control the speed at which the sequencer goes thru the steps, determine how many steps are used (up to the maximum available), choose which steps are active or inactive, set the control voltage and duration (gate time) for every step, and assign the output to a synthesizer element. Many step sequencers also have several rows of controls for each step. You can assign these Individual rows to different destinations, producing layered patterns within the sets of steps.
The step sequencer offers a type of modulation source similar to the output of a sample-and-hold LFO. However, it has much greater control. Whereas the sample-and-hold oscillator can usually synchronize its stepped output to a tempo or rhythm, the output levels of steps are random and non-repeating. Step sequencers, by contrast, not only sync the tempo but allow you to determine the exact output level of every step. You can also activate and deactivate individual steps. Additionally, by adjusting the gate time or duration of the steps create longer or shorter note values.
Now and then
Many step sequencers now provide more than sixteen steps. Some even allow you to create several measures worth of pulses. It is also increasingly common to create more complex rhythms than just eight and sixteen notes, especially for complete pieces of music. However, the step sequencer still remains an important modulator source for creating rhythmically pulsed effects in your sounds.
Sequencers were very popular back in the day. Especially with old school drum machines, synthesizers and other means to a hardware and analog setup before computers were big in the music production industry. Music software nowadays can essentially edit your ‘steps’ to a beat in a more advanced, user-friendly manner. Nevertheless many producers today prefer step sequencers not only for their production setup but when performing on stage as well. Some even use step sequencers as ‘on-the-fly’ recording in front of an audience, not only on stage but perhaps outside for a creative and fun show.